Overweight and Obesity

Is Your Child Overweight?

Body mass index (BMI) uses height and weight measurements to estimate how much body fat a person has. To calculate BMI, divide weight in kg by height in meters squared; for pounds and inches, divide weight by height squared and multiply the result by the conversion factor 703.

An easier way to measure BMI is to use a BMI calculator. Once you know your child's BMI, it can be plotted on a standard BMI chart. Kids fall into one of four categories:

1. underweight: BMI below the 5th percentile
2. normal weight: BMI at the 5th and less than the 85th percentile
3. overweight: BMI at the 85th and below 95th percentiles
4. obese: BMI at or above 95th percentile

BMI is not a perfect measure of body fat and can be misleading in some situations. For example, a muscular person may have a high BMI without being overweight (because extra muscle adds to a body weight — but not fatness). In addition, BMI may be difficult to interpret during puberty when kids are experiencing periods of rapid growth. It's important to remember that BMI is usually a good indicator — but is not a direct measurement — of body fat.

If you're worried that your child or teen may be overweight, make an appointment with your doctor, who can assess eating and activity habits and make suggestions on how to make positive changes. The doctor may also decide to screen for some of the medical conditions that can be associated with obesity.

Depending on your child's BMI, age, and health, the doctor may refer you to a registered dietitian for additional advice and, possibly, may recommend a comprehensive weight management program.

The Effects of Obesity

Obesity increases the risk for serious health conditions like type 2 diabetes, high blood pressure, and high cholesterol — all once considered exclusively adult diseases. Obese kids also may be prone to low self-esteem that stems from being teased, bullied, or rejected by peers.

Kids who are unhappy with their weight may be more likely than average-weight kids to:

• develop unhealthy dieting habits and eating disorders, such as anorexia nervosa and bulimia
• be more prone to depression
• be at risk for substance abuse

Overweight and obese kids are at risk for developing medical problems that affect their present and future health and quality of life, including:

• high blood pressure, high cholesterol and abnormal blood lipid levels, insulin resistance, and type 2 diabetes
  
• bone and joint problems
  
• shortness of breath that makes exercise, sports, or any physical activity more difficult and may aggravate the symptoms or increase the chances of developing asthma
  
• restless or disordered sleep patterns, such as obstructive sleep apnea
  
• tendency to mature earlier (overweight kids may be taller and more sexually mature than their peers, raising expectations that they should act as old as they look, not as old as they are; overweight girls may have irregular menstrual cycles and fertility problems in adulthood)
• liver and gall bladder disease
  
• depression

Cardiovascular risk factors present in childhood (including high blood pressure, high cholesterol, and diabetes) can lead to serious medical problems like heart disease, heart failure, and stroke as adults. Preventing or treating overweight and obesity in kids may reduce the risk of developing cardiovascular disease as they get older.

Causes of Overweight

A number of factors contribute to becoming overweight. Genetics, lifestyle habits, or a combination of both may be involved. In some instances, endocrine problems, genetic syndromes, and medications can be associated with excessive weight gain.

Much of what we eat is quick and easy — from fat-laden fast food to microwave and prepackaged meals. Daily schedules are so jam-packed that there's little time to prepare healthier meals or to squeeze in some exercise. Portion sizes, in the home and out, have grown greatly.

Plus, now more than ever life is sedentary — kids spend more time playing with electronic devices, from computers to handheld video game systems, than actively playing outside. Television is a major culprit.

Kids younger than 6 spend an average of 2 hours a day in front of a screen, mostly watching TV, DVDs, or videos. Older kids and teens spend almost 4 hours a day watching TV, DVDs, or videos. When computer use and video games are included, time spent in front of a screen increases to over 51/2 hours a day! Kids who watch more than 4 hours a day are more likely to be overweight compared with kids who watch 2 hours or less.

Not surprisingly, TV in the bedroom is also linked to increased likelihood of being overweight. In other words, for many kids, once they get home from school, virtually all of their free time is spent in front of one screen or another.

The American Academy of Pediatrics (AAP) currently recommends limiting the time kids over 2 years of age spend in front of a screen to no more than 1-2 hours. The AAP also discourages any screen time for children younger than 2 years.

Many kids don't get enough physical activity. Although physical education (PE) in schools can help kids get up and moving, more and more schools are eliminating PE programs or cutting down the time spent on fitness-building activities. One study showed that gym classes offered third-graders just 25 minutes of vigorous activity each week.

Current guidelines recommend that kids over 2 years of age get at least 60 minutes of moderate to vigorous physical activity on most, preferably all, days of the week.

Genetics also play a role — genes help determine body type and how your body stores and burns fat just like they help determine other traits. Genes alone, however, cannot explain the current obesity crisis. Because both genes and habits can be passed down from one generation to the next, multiple members of a family may struggle with weight.

People in the same family tend to have similar eating patterns, maintain the same levels of physical activity, and adopt the same attitudes toward being overweight. Studies have shown that a child's risk of obesity greatly increases if one or more parent is overweight or obese.

Preventing Overweight and Obesity

The key to keeping kids of all ages at a healthy weight is taking a whole-family approach. It's the "practice what you preach" mentality. Make healthy eating and exercise a family affair. Get your kids involved by letting them help you plan and prepare healthy meals, and take them along when you go grocery shopping so they can learn how to make good food choices.

And avoid falling into these common food/eating behavior traps:

• Don't reward kids for good behavior or try to stop bad behavior with sweets or treats. Come up with other solutions to modify their behavior.
  
• Don't maintain a clean-plate policy. Be aware of kids' hunger cues. Even babies who turn away from the bottle or breast send signals that they're full. If kids are satisfied, don't force them to continue eating. Reinforce the idea that they should only eat when they're hungry.
  
• Don't talk about "bad foods" or completely eliminate all sweets and favorite snacks from kids' diets. Kids may rebel and overeat these forbidden foods outside the home or sneak them in on their own.

Recommendations by Age

Additional recommendations for kids of all ages:

• Birth to age 1: In addition to its many health benefits, breastfeeding may help prevent excessive weight gain. Though the exact mechanism is not known, breastfed babies may be more able to control their own intake and follow their own internal hunger cues.
  
• Ages 2 to 6: Start good habits early. Help shape food preferences by offering a variety of healthy foods. Encourage kids' natural tendency to be active and help them build on developing skills.
  
• Ages 7 to 12: Encourage kids to be physically active every day, whether through an organized sports team or a pick-up game of soccer during recess. Keep your kids active at home, too, through everyday activities like walking and playing in the yard. Let them be more involved in making good food choices, such as packing lunch.
  
• Ages 13 to 17: Teens like fast food, but try to steer them toward healthier choices like grilled chicken sandwiches, salads, and smaller sizes. Teach them how to prepare healthy meals and snacks at home. Encourage teens to be active every day.
  
• All ages: Cut down on TV, computer, and video game time and discourage eating while watching the tube. Serve a variety of healthy foods and eat meals together as often as possible. Encourage kids to have at least five servings of fruits and vegetables a day, limit sugar-sweetened beverages, and eat breakfast every day.

If you eat well, exercise regularly, and incorporate healthy habits into your family's daily life, you're modeling a healthy lifestyle for your kids that will last. Talk to them about the importance of eating well and being active, but make it a family affair that will become second nature for everyone.

Most of all, let your kids know you love them — no matter what their weight — and that you want to help them be happy and healthy.

Reviewed by: Mary L. Gavin, MD
Date reviewed: February 2009